1. Technical Field
The present disclosure relates to color filters, and particularly to a color filter having improved pixel structure.
2. Description of Related Art
Color filters are widely used. For example, liquid crystal displays (LCD) need a color filter installed therein to produce and display color images.
Referring to FIG. 3 and FIG. 4, a conventional color filter 100 generally includes a base board 10, a shielding portion 11, a pixel portion 12 and an electrode layer 13. The base board 10 is a transparent board. The shielding portion 11 is a black matrix made of resin or chrome and defining a plurality of through holes therein. The shielding portion 11 is formed on the base board 10 to shield portions of the base board 10 and the base board 10 covers the bottoms of the through holes to form a plurality of wells 112. The pixel portion 12 includes a plurality of pixels 120, and each pixel 120 includes a plurality of sub-pixels 121/122/123/124. In fabrication, the pixel portion 12 is made of colored transparent materials, such as resin. The wells 112 are filled with the colored transparent materials to form the sub-pixels 121/122/123/124, and these sub-pixels 121/122/123/124 cooperatively form the pixels 120. Particularly, each pixel 120 is a square area including four adjacent square sub-pixels 121, 122, 123, 124, wherein the sub-pixel 121 is red, the sub-pixel 123 is blue, and the sub-pixels 122, 124 are green. Thus, light passing through the pixel 120 can form a spectrum of visible colors. The electrode layer 13 is a transparent conductive film made of indium tin oxide (ITO), which is formed on the shielding 11 and the pixel portion 12 to sandwich the shielding 11 and the pixel portion 12 between the base board 10 and the electrode layer 13.
In assembly, the color filter 100 is mounted on an electronic device (e.g., a mobile phone or a PDA) and used as a portion of a display of the electronic device. The base board 10 is positioned outside, and the electrode layer 13 is positioned inside and towards a subsidiary electrode layer (not shown) of the display. Liquid crystal (not shown) is disposed between the electrode layer 15 and the subsidiary electrode layer.
In use, electric potentials are disposed on the two electrode layers to generate an electric field between the two electrode layers. The liquid crystal is controlled to have various levels of brightness by the electric field to form images. A backlight (not shown) is provided and emits light travelling through the subsidiary electrode layer, the liquid crystal, and then the color filter 100. When light arrives at the pixel 120, the sub-pixels 121, 122, 123, 124 respectively allow red, green and blue light to pass through. Thus, the light emitting from the pixel 120 is colored by a mixture of the colors emitting from the sub-pixels 121, 122, 123, 124. When the luminance of light passing through the sub-pixels 121/122/123/124 is varied, the color of the light emitting from the pixel 120 can be changed. Therefore, the pixels 120 can respectively change color and brightness, and light passing through the plurality of pixels 120 can cooperatively form colored images. The black matrix 13 shields opaque portions adjacent to the color filter 100 (e.g., wires mounted adjacent to the color filter 100) and prevents optical interferences between adjacent pixels 120 or sub-pixels 121/122/123/124.
However, in the color filter 100, the sub-pixels 121/122/123/124 have only three basic colors. Thus, the number of colors capable of being displayed by each pixel 140 may be less, and the color gamut of the color filter 100 may be narrow. Furthermore, each sub-pixel 121/122/123/124 only allows light in one corresponding basic color (red or green or blue) to pass through. Light arriving at a sub-pixel 121/122/123/124 will be blocked if the color of the light is different to the color of the sub-pixel 121/122/123/124. Therefore, if the areas of the sub-pixels 121, 122, 123 and 124 are equal to each other, red or blue light can only pass through about ¼ transparent area of a pixel 120 (i.e., the red sub-pixel 121 or the blue sub-pixel 123), and green light can only pass through about ½ transparent area of a pixel 120 (i.e., the green sub-pixels 122 and 124). Thus, much light power of the backlight will be wasted, and a luminance of the display using the color filter 100 may be decreased.
Therefore, there is room for improvement within the art.